Neurophysiological correlates of laboratory-induced aggression in young men with and without a history of violence

Distinct brain dynamics and networks for processing short and long auditory time intervals

Psychophysical studies suggest that time intervals above and below 1.2 s are processed differently in the human brain. However, the neural underpinnings of this dissociation remain unclear. Here, we investigate whether distinct or common brain networks and dynamics support the passive perception of short (below 1.2 s) and long (above 1.2 s) empty time intervals. Twenty participants underwent an EEG recording during an auditory oddball paradigm with .8- and 1.6-s standard time intervals and deviant intervals either shorter (early) or longer (delayed) than the standard interval. We computed the auditory ERPs for each condition at the sensor and source levels. We then performed whole brain cluster-based permutation statistics for the CNV, N1 and P2, components, testing deviants against standards. A CNV was found only for above 1.2 s intervals (delayed deviants), with generators in temporo-parietal, SMA, and motor regions. Deviance detection of above 1.2 s intervals occurred during the N1 period over fronto-central sensors for delayed deviants only, with generators in parietal and motor regions. Deviance detection of below 1.2 s intervals occurred during the P2 period over fronto-central sensors for delayed deviants only, with generators in primary auditory cortex, SMA, IFG, cingulate and parietal cortex. We then identified deviance related changes in directed connectivity using bivariate Granger causality to highlight the networks dynamics associated with interval processing above and below 1.2. These results suggest that distinct brain dynamics and networks support the perception of time intervals above and below 1.2 s.

Brain responses in aggression-prone individuals: A systematic review and meta-analysis of functional magnetic resonance imaging (fMRI) studies of anger- and aggression-eliciting tasks

Reactive aggression in response to perceived threat or provocation is part of humans' adaptive behavioral repertoire. However, high levels of aggression can lead to the violation of social and legal norms. Understanding brain function in individuals with high levels of aggression as they process anger- and aggression-eliciting stimuli is critical for refining explanatory models of aggression and thereby improving interventions. Three neurobiological models of reactive aggression - the limbic hyperactivity, prefrontal hypoactivity, and dysregulated limbic-prefrontal connectivity models - have been proposed. However, these models are based on neuroimaging studies involving mainly non-aggressive individuals, leaving it unclear which model best describes brain function in those with a history of aggression. We conducted a systematic literature search (PubMed and Psycinfo) and Multilevel Kernel Density meta-analysis (MKDA) of nine functional magnetic resonance imaging (fMRI) studies (eight included in the between-group analysis [i.e., aggression vs. control groups], five in the within-group analysis). Studies examined brain responses to tasks putatively eliciting anger and aggression in individuals with a history of aggression alone and relative to controls. Individuals with a history of aggression exhibited greater activity in the superior temporal gyrus and in regions comprising the cognitive control and default mode networks (right posterior cingulate cortex, precentral gyrus, precuneus, right inferior frontal gyrus) during reactive aggression relative to baseline conditions. Compared to controls, individuals with a history of aggression exhibited increased activity in limbic regions (left hippocampus, left amygdala, left parahippocampal gyrus) and temporal regions (superior, middle, inferior temporal gyrus), and reduced activity in occipital regions (left occipital cortex, left calcarine cortex). These findings lend support to the limbic hyperactivity model in individuals with a history of aggression, and further indicate altered temporal and occipital activity in anger- and aggression-eliciting conditions involving face and speech processing.

Neural Correlates of Decisions in Quasi-Realistic, Affective Social Interactions in Individuals With Violence-Related Socialization

Appropriate social behavior in aggressive-provocative interactions is a prerequisite for a peaceful life. In previous research, the dysfunctions of the control of aggression were suggested to be modulated by enhanced bottom-up (sub-cortically driven) and reduced top-down (iso-cortical frontal) processing capability. In the present study, two groups of individuals with enhanced (EG) and normal (NG) experiences of violent acts during their socialization made binary behavioral decisions in quasi-realistic social interactions. These interactions were presented in short video clips taken from a first-person perspective. The video clips showed social interaction scenarios oriented on realistic everyday life situations. The behavioral data supported the distinct affective qualities of three categories of social interactions. These categories were labeled as aggressive–provocative, social–positive, and neutral–social interactions. Functional neuroimaging data showed extended activation patterns and higher signal intensity for the NG compared to the EG in the lateral inferior frontal brain regions for the aggressive provocative interactions. Furthermore, the peri-aqueductal gray (PAG) produced enhanced activations for the affective interaction scenarios (i.e., aggressive-provocative and social-positive) in both groups and as a trend with the medium effect size for the neutral interactions in the EG. As the individuals in the EG did not show open aggression during the functional MRIA (fMRI) investigation, we concluded that they applied individual self-control strategies to regulate their aggressive impulses immediately. These strategies appeared to be top-down regulated through the dorsal frontal brain areas. The predominant recruitment of the heteromodal cortices during the neural processing of complex social interactions pointed to the important role of the learning history of individuals and their socialization with differing levels of violent experiences as crucial modulators in convicts. Our data suggest that building or strengthening the association between prototypical social contexts (e.g., aggressive-provocative interactions) and appropriate behaviors as a response to it provides a promising approach to successfully re-socialize people with a delinquent history.

The influence of relationship closeness and desire for forgiveness on interpersonal forgiveness

This study aimed to investigate the moderating effect of the desire for forgiveness on the association between relationship closeness and interpersonal forgiveness using event-related potentials (ERPs). We recruited forty student participants (20 males and 20 females) to complete the modified Taylor Aggression Paradigm (TAP), which was used to induce the offensive experience and record the victim's level of reactive aggression toward the offenders. Results indicated that for the internal intention of forgiveness behavior, when the desire for forgiveness was not expressed, participants were more forgiving of close offenders than strangers; when the desire for forgiveness was expressed, the internal intention of forgiveness behavior for strangers was similar to that for close offenders. Regarding the external performance of forgiveness behavior, whether the offender expressed the desire for forgiveness or not, participants exhibited more external performance of forgiveness behaviors toward the close offenders than the strangers. Furthermore, the decision-related negativity (DRN)-a negative component associated with aggressiveness-was larger when participants were considering the punishment of strangers when no desire for forgiveness was expressed. There was no significant difference when the desire for forgiveness was expressed. Moreover, the feedback-related negativity (FRN)-a negative component reflecting the evaluation of the valence of an outcome-was larger when participants lost a trial against strangers when no desire for forgiveness was expressed. No such difference was observed in both opponents when the desire for forgiveness was expressed. These findings confirmed that the desire for forgiveness moderated the association between relationship closeness and interpersonal forgiveness.

Response-locked component of error monitoring in psychopathy: A systematic review and meta-analysis of error-related negativity/positivity

Evidence suggests that psychopathic individuals display difficulties to adapt their behavior in accordance with the demands of the environment and show altered performance monitoring. Studies investigating the error-related negativity (ERN) and the error-positivity (Pe) as electrophysiological markers of error monitoring reported contradictory results for this population. To explain these discrepancies, we hypothesized that psychopathy dimensions influence electrophysiological outcomes. We predicted that individuals with impulsive-antisocial features would display abnormal ERN compared to individuals with interpersonal-affective features. A systematic review and meta-analysis of studies investigating ERN and Pe components were conducted. A factorial analysis was undertaken to investigate the role of psychopathy dimensions on ERN and Pe. Compared to controls, psychopathic individuals (n = 940) showed a reduced ERN and Pe amplitude. The factorial analysis indicates a dissociation regarding the construct of psychopathy. The models reported that psychopathic individuals related specifically to the interpersonal-affective dimension displayed normal ERN component and efficient error-monitoring, while psychopathic individuals with a marked impulsive-antisocial dimension display a decreased ERN component and altered performance monitoring.

High levels of psychopathic traits increase the risk of transferring reactive aggression to innocent people after provocation: Evidence from an ERP study

This study investigated the neuropsychological underpinnings of reactive aggression toward innocent people in a student population with different levels of psychopathic traits. While recording event-related potentials, participants (divided into high/low psychopathic [HP/LP] traits groups) competed against two fictitious opponents in a modified Taylor Aggression Paradigm. We found that the HP group compared to the LP group selected more often high-intensity punishment for the second innocent opponent after being provoked by the first opponent. Further, a more negative N2 and a smaller P3 was found in the HP group while punishing the innocents-reflecting a tendency on antisocial-aggressive behavior. Finally, both groups showed a more negative FRN for losing than winning trials when seeing the outcome of the game. Our results suggest that high psychopathic traits increase the risk of transferring provoked aggression to innocent people-offering a psychophysiological perspective for explaining and predicting aggression against the innocents in social interactions.

Psychosocial intervention in at-risk adolescents: using event-related potentials to assess changes in decision making and feedback processing

Decision making and feedback processing are two important cognitive processes that are impacted by social context, particularly during adolescence. The current study examined whether a psychosocial intervention could improve psychological wellbeing in at-risk adolescent boys, thereby improving their decision making and feedback processing skills. Two groups of at-risk adolescents were compared: those who were relatively new to a psychosocial intervention, and those who had engaged over a longer time period. Electroencephalography was recorded while the young people participated in a modified version of the Taylor Aggression Paradigm. The late positive potential (LPP) was measured during the decision phase of the task (where participants selected punishments for their opponents). The feedback-related negativity (FRN) and P3 components were measured during the task's outcome phase (where participants received 'win' or 'lose' feedback). Adolescents who were new to the intervention (the minimal-intervention group) were harsher in their punishment selections than those who had been engaged in the program for much longer. The minimal-intervention group also showed an enhanced LPP during the decision phase of the task, which may be indicative of immature decision making in that group. Analysis of the FRN and P3 amplitudes revealed that the minimal-intervention group was physiologically hypo-sensitive to feedback, compared with the extended-intervention group. Overall, these findings suggest that long-term community-based psychosocial intervention programs are beneficial for at-risk adolescents, and that event-related potentials can be employed as biomarkers of therapeutic change. However, because participants were not randomly allocated to treatment groups, alternative explanations cannot be excluded until further randomized controlled trials are undertaken.

Juveniles with a history of violent behavior show cognitive performance and electrophysiology consistent with inhibitory control and emotional feedback processing problems

Inhibitory control and the effects of negative emotional feedback were investigated in adolescents with a history of violent behavior and normal adolescents using the Taylor Aggression Paradigm (TAP), a task simulating real situations of social interaction to elicit aggressive behavior and negative emotions, with concurrent event related potential recordings. The Reactive Proactive Aggression Questionnaire (RPAQ), the Barratt Impulsiveness Scale (BIS) and the Negative Mood Regulation (NMR) Scale were also presented. These showed that reactive scores, proactive scores, and BIS scores were all significantly higher for the violent offender group whereas scores from the NMR scale were significantly lower for this group. In the TAP, the violent offender group chose significantly higher levels of punishment, indicative of both higher proactive and higher reactive aggression, for their opponent than did the control group. The ERP data showed the N2 amplitude for the decision phase, indicative of inhibitory control, was lower for the violent offender group than for the control group, with mediation analysis showing that the N2 component was related to proactive aggression. The decision-related negativity and the feedback-related negativity in the result phase were also both lower for the violent offender group than for the control group. Adolescent violent offenders showed higher levels of aggressive behavior than normal adolescents. This is associated with both worse inhibitory control and worse negative emotion regulation. Investigation of common factors underlying these processes, in conjunction with possible ways in which they might be improved, should be a priority for future work.

Social provocation modulates decision making and feedback processing: Examining the trajectory of development in adolescent participants

•

EEG was used to examine social provocation, decision-making and win/loss feedback.

•

Results revealed that social provocation modules cognitive and brain responses.

•

Neural responses differed between younger and older adolescents.

•

Social context is crucial to adolescent brain and behavioural development.

Increasingly, research is turning to the ways in which social context impacts decision making and feedback processing in adolescents. The current study recorded electroencephalography to examine the trajectory of development across adolescence, with a focus on how social context impacts cognition and behaviour. To that end, younger (10–12 years) and older (14–16 years) adolescents played a modified Taylor Aggression Paradigm against two virtual opponents: a low-provoker and a high-provoker. During the task's decision phase (where participants select punishment for their opponent), we examined two event-related potentials: the N2 and the late positive potential (LPP). During the outcome phase (where participants experience win or loss feedback), we measured the feedback related negativity (FRN). Although N2 amplitudes did not vary with provocation, LPP amplitudes were enhanced under high provocation for the younger group, suggesting that emotional reactivity during the decision phase was heightened for early adolescents. During the outcome phase, the FRN was reduced following win outcomes under high provocation for both groups, suggesting that a highly provocative social opponent may influence the reward response. Collectively, the data argue that social context is an important factor modulating neural responses in adolescent behavioural and brain development.

Short-term effects of prosocial video games on aggression: an event-related potential study

Previous research has shown that exposure to violent video games increases aggression, whereas exposure to prosocial video games can reduce aggressive behavior. However, little is known about the neural correlates of these behavioral effects. This work is the first to investigate the electrophysiological features of the relationship between playing a prosocial video game and inhibition of aggressive behavior. Forty-nine subjects played either a prosocial or a neutral video game for 20 min, then participated in an event-related potential (ERP) experiment based on an oddball paradigm and designed to test electrophysiological responses to prosocial and violent words. Finally, subjects completed a competitive reaction time task (CRTT) which based on Taylor's Aggression Paradigm and contains reaction time and noise intensity chosen as a measure of aggressive behavior. The results show that the prosocial video game group (compared to the neutral video game group) displayed smaller P300 amplitudes, were more accurate in distinguishing violent words, and were less aggressive as evaluated by the CRTT of noise intensity chosen. A mediation analysis shows that the P300 amplitude evoked by violent words partially mediates the relationship between type of video game and subsequent aggressive behavior. The results support theories based on the General Learning Model. We provide converging behavioral and neural evidence that exposure to prosocial media may reduce aggression.